Esa's comet-chasing spacecraft to wake up after 3 years of sleep

The European Space Agency (Esa) is today performing a challenging operation, waking up the comet-chasing spacecraft Rosetta after 957 days of hibernation.

The waking-up manoeuvre has commenced today at 10am GMT with Rosetta’s internal clock turning on its internal computers. The spacecraft will require up to seven hours to warm up its star-tracking navigation system, fire its rocket thrusters in order to slow down its spin to be able to turn on a transmitter and beam a message to the Earth. Controllers at Esa’s European Space Operations Centre in Darmstadt, Germany, hope to confirm the spacecraft has been successfully resuscitated by 6pm GMT today.

Speaking during the media event organised by Esa at the Darmstadt control centre, the centre’s director and former German astronaut Thomas Reiter said the operation was something that has ‘never been done before’.

Rosetta, launched in 2004, is currently located some 500 million miles away from the Earth near Jupiter and heads toward a 2.4-mile in diameter comet known as 67P/Churyumov-Gerasimenko.

Later this year, in an unprecedented manoeuvre, the spacecraft will not only sail by the comet, but will insert itself into its orbit and drop a lander to the comet’s surface.

“The mission is unique not only in the terms of science but also in the terms of technology,” said Esa’s Director of Science and Robotic Exploration Alvaro Gimenez during the media event. “We are actually doing something nobody has ever done before. What we are trying to do here is extremely difficult and extremely challenging.”

When designing the 100kg lander, named Philae, Esa’s engineers had only very limited information about the actual terrain where the module will land. Equipped with two harpoons to attach itself to the comets surface, the lander is expected to reach its destination in November 2014, approaching the comet at a relatively slow speed of 1m/s and. The spacecraft will collect data about the comet’s chemical composition, hopefully shedding some light on the history of the solar system.

Comets are believed to be the pristine leftover remains from the formation of the solar system some 4.6 billion years ago.

"Rosetta should become a key element for our understanding of the history of the solar system," Stephan Ulamec, a Rosetta project manager, said in an interview with Reuters last month.

"It would be really interesting to find out whether the organic chemistry that is relevant for life is there on comets," Ulamec said.

Esa spent about €1bn on the mission that is expected to run until the end of 2015.

Since its launch from Europe’s Spaceport in Kourou on 2 March 2004, Rosetta has travelled to a distance of some 800 million kilometres from the Sun and close to the orbit of Jupiter, passing by Earth three times and Mars once, and flying past two asteroids. For the most distant part of the journey, the spacecraft was put into deep-space hibernation.